lambda¶
Description¶
Returns an anonymous function.
Syntax¶
lambda variable, …: expression
- variable, …
- Optional. One or more variables used in the right part of the expression.
- expression
- Required. Return value of the function.
Return Value¶
#TODO
Time Complexity¶
#TODO
Remarks¶
lambda expression is a shorthand way of defining a function that is not bound to a specified name during its creation.
Consider the following function:
>>> def func(a): return a + 1
...
>>> func(0)
1
>>>
The same function can be defined using lambda expression as follows:
>>> func = lambda a: a + 1
>>> func(0)
1
Both functions are the same. Note that lambda does not include a return statement. The right expression is the implicit return value. Lambda functions need not to be assigned to any variables.
Example 1¶
>>> # this example shows how to use lambda with sorted function
>>> # lambda function is grabage collected after it has been used
>>> # (there is no reference to it to keep it alive)
>>> sorted(['A', 'b', 'C'], key=lambda x: x.lower())
['A', 'b', 'C']
Example 2¶
>>> # this is a code snippet from a Tkinter gui app
>>> # in this case lambda is quite convenient
>>> self.btn_cancel = Button(self.progress_container, text='Cancel',
>>> command=lambda: subprocess.call('taskkill /f /im uberzip.exe',
>>> shell=True))
See also¶
#TODO